Sprinkler irrigation

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1. Subsurface irrigation methods As suggested by the name, the application of water to fields in this type of irrigation system is below the ground surface so that it is supplied directly to the root zone of the plants. The main advantages of these types of irrigation is reduction of evaporation losses and less hindrance to cultivation works which takes place on the surface. There may be two ways by which irrigation water may be applied below ground and these are termed as: • Natural sub-surface irrigation method • Artificial sub-surface irrigation method

2. Natural Sub-surface irrigation method Under favorable conditions of topography and soil conditions, the water table may be close enough to the root zone of the field of crops which gets its moisture due to the upward capillary movement of water from the water table . The natural presence of the water table may not be able to supply the requisite water throughout the crop growing season. However, it may be done artificially by constructing deep channels in the field which may be filled with water at all times to ensure the presence of water table at a desired elevation below the root zone depth .

3. Natural Sub-surface irrigation method Though this method of irrigation is excellent from both water distribution and labour saving points of view. it is favorable mostly for the following • The soil in the root zone should be quite permeable • There should be an impermeable substratum below the water table to prevent deep percolation of water . • There must be abundant supply of quality water that is one which is salt free, otherwise there are chances of upward movement of these salts along with the moisture likely to lead the conditions of salt incrustation on the surface.

4. Artificial subsurface irrigation method The concept of maintaining a suitable water table just below the root zone is obtained by providing perforated pipes laid in a network pattern below the soil surface at a desired depth. This method of irrigation will function only if the soil in the root zone has high horizontal permeability to permit free lateral movement of water and low vertical permeability to prevent deep percolation of water. For uniform distribution of water percolating into the soil, the pipes are required to be very closely spaced, say at about 0.5m.

5. Artificial subsurface irrigation method Further , in order to avoid interference with cultivation the pipes have to be buried not less than about 0.4m below the ground surface. This method of irrigation is not very popular because of the high expenses involved, unsuitable distribution of subsurface moisture in may cases, and possibility of clogging of the perforation of the pipes.

6. Sprinkler Irrigation System Sprinkler irrigation is a method of applying water which is similar to natural rainfall but spread uniformly over the land surface just when needed and at a rate less than the infiltration rate of the soil so as to avoid surface runoff from irrigation. This is achieved by distributing water through a system of pipes usually by pumping which is then sprayed into the air through sprinklers so that it breaks up into small water drops which fall to the ground.

7. Sprinkler Irrigation System The system of irrigation is suitable for undulating lands, with poor water availability, sandy or shallow soils, or where uniform application of water is desired. No land leveling is required as with the surface irrigation methods. Sprinklers are, however, not suitable for soils which easily form a crust. The water that is pumped through the pump pipe sprinkler system must be free of suspended sediments. As otherwise there would be chances of blockage of the sprinkler nozzles.

8. Sprinkler Irrigation System In sprinkler irrigation, water is conveyed under pressure through pipes to the area to be irrigated where it is passed out through or sprinklers the system comprises four main parts i .  Power generator ii.  Pump iii. Pipeline and iv. Sprinkler

9. Sprinkler Irrigation System The power generator may be electrical or mechanical. A centrifugal pump may be used for suction lift up to 37 to 50 cm . A piston type pump is preferable where water is very deep . The pipe consists of two sections, the main line and the laterals. The main line may be permanently buried underground or may be laid above ground, if it is to be used on a number of fields . The main pipes are usually made of steel or iron .

10. Sprinkler Irrigation System The laterals are lightweight aluminum pipes and are usually portable . The sprinkler nozzles may be single or double, revolving or stationery and mounted or riser pipes attached to riser. Each sprinkler head applies water to circular area whose diameter depends up on the size of water, which varies from ¼ to ¾ inch per hour is determined by selecting the proper combination of nozzles.

11. Sprinkler Irrigation System Adaptations: 1 ) A dependable supply of water 2 ) Uneven topography 3 ) Shallow soils. 4 ) Close growing crops .

12. Sprinkler Irrigation System Advantages: It ensures uniform distribution of water It is adaptable to most kinds of soil. It offers no hindrance to the use of farm implements Fertilizers material may be evenly applied through sprinklers. This is done by drawing liquid fertilizer solution slowly in to the pipes on the suction side of the pump so that the time of application varies from 10 to 30 minutes.

13. Sprinkler Irrigation System Advantages : 5 ) Water losses are reduced to a minimum extent 6) More land can be irrigated 7) Costly land leveling operations are not necessary and 8) The amount of water can be controlled to meet the needs of young seedling or mature crops.

14. Sprinkler Irrigation System Disadvantage: 1)  The initial cost is rather very high. 2)  Any cost of power to provide pressure must be added to the irrigation charges. 3)  Wind interferes with the distribution pattern, reducing spread or increasing application rate near lateral pipe. 4)  There is often trouble from clogged nozzle or the failure of sprinklers to revolve.

15. Sprinkler Irrigation System Disadvantage: 5) The cost of operations and maintaince is very high. Labour requirement for moving a pipe and related work approximately nearly one hour per irrigation. 6) It requires a dependable constant supply of water free slit and suspended matter and 7 ) It is suitable for high value crops

16. Drip Irrigation It is termed as trickle irrigation also and can be define as slow and frequent application of water to the plant root zone under low pressure . The drip irrigation is an advanced method of irrigation suitable for water scarcity areas. It uses the water very economically and efficient.

17. Drip Irrigation It applies the correct quantity of water to the plant at the root zone through a network of tubing’s. The design of drip system is simple. These requirements are pipes, accessories and other equipment. This method can be very well adopted for wide spaced crops like Coconut, Mango, Sapota , Banana, etc  

18. Advantages of Drip Irrigation 1. Maximum use of available water. 2. No water being available to weeds. 3. Maximum crop yield. 4. High efficiency in the use of  fertilizers. 5. Less weed growth and restricts population of potential hosts. 6. Low labour and relatively low operation cost. 7. No soil erosion.

19. Advantages of Drip Irrigation 8 . Improved infiltration in soil of low intake. 9. Ready adjustment to sophisticated automatic control. 10. No runoff of fertilizers into ground water. 11. Less evaporation losses of water as compared to surface irrigation. 12. Improves seed germination. 13. Decreased to tillage operations.

20. Disadvantages of Drip Irrigation In spite of the fact that drip irrigation has so many potential benefits , they’re a certain limitation also, there are as follow: 1. Sensitivity to clogging 2. Moisture distribution problem 3. Salinity hazards 4. High cost compared to furrow. 5. High skill is required for design, install and operation.